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Derek Jackson, MRIA: Coastal Geomorphologist

15 July 2021

Professor Jackson’s work as a geomorphologist, examining changes in physical landscapes over time and the processes that drive them, has taken him from Ireland’s coastal dunefields to the Caribbean, and more recently (virtually) to the surface of Mars.

Derek Jackson MRIA, Professor of Coastal Geomorphology, School of Geography and Environmental Sciences, Ulster University, Coleraine

As a coastal geomorphologist, my research examines the physical landforms found within coastal and nearshore zones, how these change over time, and what processes drive these changes.

Humans are living through a period of unprecedented environmental change, with many of the planet’s natural systems being altered at alarming rates. The speed of this change is driven by the impact we are having on the planet’s finely balanced environmental system. At the coast, where the atmosphere, land and oceans meet, we can see the signs of climate change sometimes more vividly than elsewhere. Here, we are experiencing at the global level, increasing sea levels, more storms, bigger storms and rapid changes to the coastline itself. My research involves examining how this change takes place. I study the physical fluctuations at coasts through various timescales; making use of numerical computer modelling as well as field measurements in coastal environments, I examine the important dynamics involved in these physical changes that are picked up through the alteration of coastal landforms over time.

My specific area of research involves studying the physical processes happening at the coast and how these create change in the (sandy) landforms that we find there. The coastal system is not simply a thin line between the sea and the land; instead, it includes a zone stretching distances of several kilometers offshore (the shoreface) as well as many kilometers inland, incorporating many types of landforms. Examination of the processes that are causing coastal change must begin much further seaward from the beach than most people realise. Using high-end computing, we can run wave and current models from the offshore zone and then right across the nearshore and beach, to inform us of the predicted movements of water, and of sediments.

The shoreface is where large stores of (mostly) sand and other material are located and therefore acts as an important supplier of sand to beaches: waves and currents help to move sand from the shoreface onto the shore, where eventually, if conditions are right in terms of shelter and low energy impacts, it forms a beach. These processes shape our coastlines and give us the beaches that we see today. I am interested in how this system operates over timescales of millennia.

I am also interested in actual events such as high-energy marine storms. With the acceleration in climate change, we are experiencing more and more storm events with more extremes being recorded, and the coast reveals this usually in the form of severe erosion. My work has taken me around the world, examining beach and dune systems and looking at extreme events that strike coasts in many parts of Europe, South Africa, America and the Caribbean. Recent work has involved studying the Category 5 Hurricane Irma in 2017 and its devastating impact on Antigua and Barbuda. Using computer wave modelling and remote sensing images to extract sea-bed depths, we were able to examine before-and-after-event scenarios. We intend to use this information for local emergency planning for future events. Our research here also provides information about where on the coasts of low-lying islands is most vulnerable to wave erosion from these mega events; having this knowledge can help save lives and reduce infrastructure loss.

When the sand on the beach dries and it becomes windy enough, sand will blow inland, collecting in the form of sand dune landforms, which can stretch up to several kilometers from the shore. Coastal dunefields in Ireland are some of highest and most extensive in the world. They represent a unique catalogue of environmental events in the last 6000–7000 years, since the beginning of conditions favourable to the formation of dunefields. Wind is a key driver of change to the dunes, as is the presence of vegetation. In recent years I have made use of 3D computer modelling of wind over beaches and dunes to examine its role in driving change. For such modelling, a detailed record of the underlying terrain surface is required; data on the terrain is incorporated into the model along with data on atmospheric physics and used to simulate complex flow over various surfaces.

In an unusual twist, I have recently investigated how we can also use this modelling method on the surface of Mars, enabling for the first time fine-scale investigations of how sand gets moved on another planet. This has led to funded research via the UK Space Agency and linked to the European Space Agency’s 2022 Rover mission to Mars. In that work, we are investigating the area around the landing zone for the Rover and modelling the winds moving across it, sculpting the surface and shifting material. For me, this is exciting science in action, and I look forward to seeing the project unfold successfully.

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